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(10 of 11)www.advmat.de www.advancedsciencenews.com steps in the pre-edge region of the XAS spectra (10 167-10 347 eV), 0.25 eV steps in the XANES region (10 347-10 417 eV). In the extended X-ray absorption fine structure region spectra were collected, in steps of 0.035k to a maximum of 10k, with count time increasing linearly from 2 up to 4 s at the end of the energy range. Multiple scans were collected for each sample. Data were preprocessed using Sakura (in-house program) and the Athena program for scan averaging, background subtraction, and edge-height normalization (Ravel and Newville, 2005). Periodically throughout the experiment, transmission scans were collected of the in-line Re foil.

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Transforming natural resources to energy sources, such as converting CH 4 to H 2 and carbon, at high efficiency and low cost is crucial for many industries and environmental sustainability. The high temperature requirement of CH 4 conversion regarding many of the current methods remains a critical bottleneck for their practical uptake. Here we report an approach based on gallium (Ga) liquid metal droplets, Ni(OH) 2 cocatalysts, and mechanical energy input that offers lowtemperature and scalable CH 4 conversion into H 2 and carbon. Mainly driven by the triboelectric voltage, originating from the joint contributions of the cocatalysts during agitation, CH 4 is converted at the Ga and Ni(OH) 2 interface through nanotriboelectrochemical reaction pathways. The efficiency of the system is enhanced when the reaction is performed at an increased pressure. The dehydrogenation of other nongaseous hydrocarbons using this approach is also demonstrated. This technology presents a possible low energy route for CH 4 conversion without involving high temperature and harsh operating conditions.

Liquid metals and alloys with high-aspect-ratio nanodimensional features are highly sought-after for emerging electronic applications. However, high surface tension, water-like fluidity, and the existence of self-limiting oxides confer specific peculiarities to their characteristics. Here, we introduce a high accuracy nanometric three-dimensional pulling and stretching method to fabricate liquid-metal-based nanotips from room- or near-room-temperature gallium-based alloys. The pulling rate and step size were controlled with a resolution of up to 10 nm and yielded different nanotip morphologies and lengths as a function of the base liquid metal alloy composition and the pulling parameters. The obtained nanotips presented high aspect ratios over lengths of a few microns and apexes between 10 and 100 nm. The liquid metal alloys were found confined within nanotips with about 10 nm apexes when vertically pulled at 100 nm/s. An amorphous gallium oxide skin was shown to cover the surface of the nanotips, while the liquid core was composed of the initial liquid metal alloys. The electrical contact established at the nanotips was characterized under dynamic conditions. The liquid metal nanotips showed an Ohmic resistance when a continuous liquid metal channel was formed, and a controllable semiconductor state corresponding to a heterojunction formed at the junction between the liquid metal phase and the gallium oxide semiconductor skin. The variable threshold voltages of the heterojunction were controlled via stretching of the nanotips with a 10 nm step resolution. The liquid metal nanotips were also used for establishing soft electronic junctions. This novel method of liquid metal nanotip fabrication with Ohmic and semiconducting behaviors will lead to exciting avenues for developing electronic and sensing devices.